I fully agree with the part about abortion and euthanasia, but the death penalty for taking innocent life is scriptural and there is nothing I know of in scripture that expressly forbids a Christian to fight and possibly kill in defense of his nation. In fact, it is recorded in the Old Testament that God commanded the Israelis to kill all the men, women, and children of the pagan tribes and nations that occupied the land of Canaan when they arrived there after forty years of wandering in the desert. Furthermore, He later disciplined the nation of Israel for allowing some pagans to continue to live and occupy a part of the land He promised to Jacob's progeny.
I don't know how to reconcile God's command to Joshua with Jesus' command to love our enemies as ourselves. Since the pagan enemies were sacrificing their own children to idols and also warring against the Israelis I can from a human POV understand Him ordering their extermination. But then that complicates knowing how to understand Jesus' command to love our Godless enemies and do good to those who persecute us. But that's no doubt due to my inability to properly understand God's word, and not due to any fault with what seems to be His contradictory commands. More personal bible study is definitely in order for me.
If you're interested, you can find a much fuller treatment of the Catholic doctrine on the death penalty and on war in the Catechism, and I can assure you that no pope is going to contradict this.